title: Receptors for IgA on human thymus cells in myasthenia gravis.
abstract: Specific surface receptors for the Fc region of human immunoglobulin A (Fc alpha R) were identified on the thymus cells of all 15 patients affected by myasthenia gravis. A large variation of the percentage of Fc alpha R bearing thymus cells was recorded (9 . 5-66 . 0%; mean value 27 . 9 +/- 17 . 8) the high values being associated in most cases with the thymus hyperplasia and the low values with a lipomatosis of the organ. Even the lowest percentage of Fc alpha R bearing cells recorded in myasthenia gravis are considerably higher than those found in normal subjects (0 . 4-4 . 1; mean value 1 . 8) demonstrating that the expression of Fc alpha R on the thymus cells is the consequence of the disease. No attempts were made to identify the cell population bearing Fc alpha R but indirect results indicate that the cells belong to E-rosette forming population, and, in some cases, to a null cell population devoid of the ability to form E and EAC rosettes, Fc alpha R can bind various IgA ligands and the binding is confined to a small fraction of IgA (not more than 5%) considered as cytophilic IgA.
mesh_terms: D000042:Absorption; D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007070:Immunoglobulin A / Q000145:classification / Q000378:metabolism*; D007137:Immunoglobulin alpha-Chains; D009157:Myasthenia Gravis / Q000276:immunology* / Q000473:pathology; D011817:Rabbits; D011961:Receptors, Fc; D012397:Rosette Formation; D013950:Thymus Gland / Q000276:immunology* / Q000473:pathology
chemical_list: D007070:Immunoglobulin A; D007137:Immunoglobulin alpha-Chains; D011961:Receptors, Fc